Methods and apparatus for cell ganging in a multislice computed tomography system

Abstract

A combination of double and triple cell ganging which resolves any incompatibility between the number of detector channels and the lower number of DAS channels without requiring any significant hardware and software changes is described. In one specific embodiment, at least some detector cells on one side of the detector outside the FOV are wired in pairs, i.e., ganged, to form a set of 2 mm channels, and on the other side of the detector outside the FOV, at least some detector cells are wired together, i.e., ganged, to form a set of 3 mm channels. Such ganging of detector cells avoids having to make any significant hardware and software changes to known multislice CT systems.

What is claimed is: 
     
       1. A detector for a computed tomography system, said detector comprising: a plurality of detector cells;   a first set of detector cells located within a field of view;   a second set of detector cells located on a first side of said field of view, at least some of said detector cells in said second set N ganged, where N is greater than or equal to one; and   a third set of detector cells located on a second side of said field of view, at least some of said detector cells in said third set M ganged, where M is greater than N.   
     
     
       2. A detector in accordance with claim 1 wherein at least some detector cells in said third set are N ganged. 
     
     
       3. A detector in accordance with claim 1 wherein N=2 and M=3. 
     
     
       4. A detector in accordance with claim 1 wherein N=1 and M=2. 
     
     
       5. A detector in accordance with claim 1 wherein said detector cells have a channel width of about 1 mm, and said N ganged detector cells have a channel width of about N mm and said M ganged detector cells have a channel width of about M mm. 
     
     
       6. A detector in accordance with claim 1 wherein said detector is a multislice detector. 
     
     
       7. A detector in accordance with claim 6 wherein said multislice array comprises 2 rows of detector cells. 
     
     
       8. A detector array in accordance with claim 6 wherein said multislice array comprises 4 rows of detector cells. 
     
     
       9. A detector in accordance with claim 1 wherein said detector is a single slice detector. 
     
     
       10. A computed tomography system, comprising: a detector comprising a plurality of detector cells, a first set of detector cells located within a field of view, a second set of detector cells located on a first side of said field of view, at least some of said detector cells in said second set N ganged, where N is greater than or equal to one, and a third set of detector cells located on a second side of said field of view, at least some of said detector cells in said third set M ganged, where M is greater than N; and   a data acquisition system coupled to said detector array.   
     
     
       11. A computed tomography system in accordance with claim 10 further comprising a processor coupled to said data acquisition system, said processor configured to under-weight data contributions from said M ganged cells and to over-weight data contributions from said N ganged cells. 
     
     
       12. A computed tomography system in accordance with claim 10 further comprising a processor coupled to said data acquisition system, said processor configured to apply a weighting factor of α(0≦α<1) to said M ganged cells and a weighting factor of 2-α to said N ganged cell. 
     
     
       13. A computed tomography system in accordance with claim 12 wherein a smooth transition zone is provided between said weighting factor of said N ganged cells and said weighting factor of said M ganged cells. 
     
     
       14. A computed tomography system in accordance with claim 13 wherein for said transition zone between said N ganged cells and said M ganged cells, a weighting factor of in accordance with: ##EQU3## is applied, where δ is the transition width, and x is chosen so that x=δ at the N-M cell boundary. 
     
     
       15. A computed tomography system in accordance with claim 10 wherein said detector cells have a channel width of about 1 mm, and said N ganged detector cells have a channel width of about N mm and said M ganged detector cells have a channel width of about M mm. 
     
     
       16. A computed tomography system in accordance with claim 10 wherein said detector is a multislice array. 
     
     
       17. A computed tomography system in accordance with claim 10 wherein said detector is a single slice detector.